1. Field of the Invention
The present invention relates generally to an electrical connecting device, and more particularly, to an electrical connecting device adapted to enhance electrical connection.
2. Description of the Prior Art
With the trend of the electronic device developed to be thin, light-weighted, miniaturized and portable, there is a need to place more terminal sets in a limited area on the electrical connecting device to correspond to increased pins placed on a central processor unit.
FIG. 1 illustrates an electrical connecting device disclosed in the China Patent Publication No. CN2833952. The electrical connecting device comprises a first base a, a first driving pin b, a cam c and a frame board d disposed on the front side of the first base a. The first base a is formed with four receiving holes a1 and a shaft hole a2. The first driving pin b is formed with a driving portion b1 and a shaft portion b2. The cam c is formed with a driven hole c1. The shaft portion b2 is able to cooperate with the driven hole c1, so that rotating the driving portion b1 is able to drive the cam c to rotate. The middle portion of the frame board d is formed with a bulging part d1, of which a center through hole d2 is formed in the center part. The frame board d further extends downward to form four foot portions d3. Each of the foot portions d3 is able to cooperate with one of the receiving holes a1, that is, the frame board d is firmly connected and disposed on the first base a.
When assembling the electrical connecting device, the first step is to dispose the cam c on the front side of the first base a and to have the driven hole c1 corresponding to the shaft hole a2. Furthermore, dispose the frame board d on the cam c to have the cam c received between the bulging part d1 and the first base a. The center through hole d2 is disposed correspondingly to the driven hole c1 and the shaft hole a2. Each of the foot portion d3 passes through one of the receiving holes a1 to firmly connect and position the frame board d on the first base a. Finally, pass the shaft potion b2 through the center through hole d2, the driven hole c1 and the shaft hole a2. In practical operation, the cam c can be driven to rotate simply by rotating the driving portion b1 with a tool.
The disadvantage of the electrical connecting device will be described in the following details. With the reaction force exerted on the pins of the central processing unit by the terminal set, the reaction force is delivered to the frame board d and the first base a solely by the shaft portion b2. Although the frame board d reinforces the first base a to a certain extent, the frame board d is positioned on the first base a but not on an electrical circuit board (not shown in the drawing). Therefore, no reaction force can be transferred away through the electrical circuit board (not shown in the drawing), which may further result in bump forming on the front side of the first base a.
Another electrical connecting device is disclosed in the specification and drawings of the U.S. patent application Ser. No. U.S. 20050054754. The electrical device comprises a second driving pin and a second base. The second base has a fastening metal sheet disposed on the front side thereof and a base hole disposed thereon correspondingly to a shaft portion disposed on the second driving pin.
The second base has the fastening metal sheet disposed on the front side thereof to reinforce the second base, which solves the problem of the bump that may form on the front side of the second base due to increasing reaction force from the terminal sets. However, because the shaft potion is directly disposed inside the base hole, the reaction force exerted to the base hole by the shaft portion increases with the increasing force that rotates the second driving pin. Therefore, without any reinforcement provided to the base hole, the shaft potion may wear the surrounding base hole and causes the base hole to expand. As a result, loosening will occur in the coordination between the shaft portion and the base hole, which will interfere on the electrical connection of the electrical connecting device.
Therefore, there is a need to design a new electrical connecting device to overcome the defection described hereinabove.